In contrast with a long-held belief, flu vaccines may not protect the elderly from hospitalizations and death, a new study suggests.
The study in the Annals of Internal Medicine found flu vaccines, which have long been recommended for seniors, may not decrease hospitalizations or mortality among elderly persons.
A better strategy to protect the elderly may be to vaccinate children, a group likely to transmit the flu, the study authors suggest.
Researchers from the University of California, Berkeley, the University of California, Santa Cruz and Clemson University conducted an observational study with data from patient surveys and administrative records for adults aged 55 to 75 living in England and Wales, where there is an age-based vaccination policy, from 2000 to 2014. They concluded that vaccination strategies that prioritize elderly people may be less effective than believed at reducing morbidity and mortality, which suggests supplementary strategies may be needed.
A strategy suggested by epidemiological models is to vaccinate children who can carry the flu, which may protect high-risk groups more than vaccinating the high-risk groups themselves, the researchers said.
The researchers said continued vaccination of seniors, particularly with high-dose vaccines, still seems appropriate, as the study results did not preclude modest effectiveness of the flu vaccine against severe outcomes.
"Our findings raise questions, however, about the overall effectiveness of a vaccination strategy that is limited to standard vaccines and focuses too much on elderly persons. Supplementary strategies, such as vaccinating children and others who are most likely to spread influenza, may also be necessary to address the high burden of influenza-related complications among older adults,” the researchers concluded.
The researchers measured hospitalization and mortality rates by month of age. Their data included 170 million episodes of care and 7.6 million deaths. Flu vaccination rates increased sharply at age 65, but there was no matching decrease in hospitalizations or death.